The present invention is directed to an arrangement for holding or mounting a glass member for a field-assisted ion exchange with annodic and cathodic contacting by melted salts. The glass member is held between two melted salt vessels, each containing the melted salt which contacts the glass member through contact openings fashioned in the vessels.
An arrangement for contacting a glass member is disclosed in an article from Electron. Lett., Apr. 15, 1982, Volume 18, No. 8. This arrangement serves the purpose of producing a geodetic lens in a glass substrate comprising a film or layer waveguide generated by a field-assisted ion exchange. To that end, the plate-shaped glass substrate, which is locally curved in a molding cycle, has a surface held by suction against the sealing surface on an underside or bottom of an evacuatable cylinder vessel for the one glass melt. The suctioned surface of the glass substrate is in contact with the glass melt in the vessel through to the contact opening, which is surrounded by the sealing surface and simultaneously prevents the melt from flowing out in a downward direction.
The underside of the suctioned glass substrate is brought into contact with the other salt melt by dipping the substrate into this melt. This melt is situated in the other vessel, whose contact opening on its upper surface is of such a size that the glass substrate can be introduced through it into the vessel.
Electrodes are arranged in the two salt melts, and these electrodes are connected by electrical lines to an anode terminal and to a cathode terminal. The electrical line of the evacuatable vessel is conducted into the interior of the vessel from above through a vacuum-tight electrical lead-through.
A similar arrangement is also disclosed in SPIE, Vol. 651 "Integrated Optical Circuit Engineering III", 1986, pp. 46-50.
These arrangements, however, are unsuitable or problematical when the contact pressure to be exerted is excessively high for the particular glass member and, for example, leads to a deformation or even destruction of the member. For example, this can be the case given extremely thin, plate-shaped glass members and/or when the ion exchange is to be carried out at a temperature above the transformation temperature T.sub.g (DIN 52 24) of the glass. The relatively high contact pressure, typically 100-1,000 mbar, leads to destruction of the glass member. However, the contact pressure, on the other hand, cannot be selected lower than about 100 mbar, since the sealing surface would otherwise become ineffective and would result in the emergence of the salt melt and in a short-circuit.